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What Kind of Triangle? is a free printable Grade 4 math worksheet on naming a triangle from its largest angle, aligned to Common Core standard 4.G.A.2. It prints 9 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two students in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.

Set 21 of 25 · the same problems every time you open this link.

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Set 1 has all 25 in a single PDF. All 25 sets ask different questions.

What Kind of Triangle?

4.G.A.2

NameDate

Write acute, right or obtuse.

1.A triangle has angles of 15°, 90° and 75°. Is it acute, right or obtuse?
2.A triangle has angles of 20°, 150° and 10°. Is it acute, right or obtuse?
3.A triangle has angles of 90°, 35° and 55°. Is it acute, right or obtuse?
4.A triangle has angles of 25°, 25° and 130°. Is it acute, right or obtuse?
5.A triangle has angles of 80°, 90° and 10°. Is it acute, right or obtuse?
6.A triangle has angles of 80°, 20° and 80°. Is it acute, right or obtuse?
7.A triangle has angles of 20°, 35° and 125°. Is it acute, right or obtuse?
8.A triangle has angles of 90°, 40° and 50°. Is it acute, right or obtuse?
9.A triangle has angles of 65°, 30° and 85°. Is it acute, right or obtuse?

LessonPrint · 4.G.A.2 · Set 21 · free to copy for classroom use

Answer key — What Kind of Triangle?

Set 21. Prints on its own sheet.

  1. 1.right
  2. 2.obtuse
  3. 3.right
  4. 4.obtuse
  5. 5.right
  6. 6.acute
  7. 7.obtuse
  8. 8.right
  9. 9.acute

Last reviewed 2026-09-05. Aligned to 4.G.A.2 of the Common Core State Standards for Mathematics.